### prefix for temporary scrap files
declare _scrap_prefix=${SCRAP_PREFIX:-scrap-}

### temporary scrap helper files
declare _scrap_version_sticker_current="${_scrap_prefix}version_sticker_current.tmp"
declare _scrap_version_sticker_verbose_current="${_scrap_prefix}version_sticker-verbose_current.tmp"
declare _scrap_version_sticker_verbose_previous="${_scrap_prefix}version_sticker-verbose_previous.tmp"
declare _scrap_demand_stop_building="${_scrap_prefix}demand-stop-building"

### gist file keys
declare _gist_key_created="created.json"
declare _gist_key_version_sticker="version-sticker.json"
declare _gist_key_version_sticker_verbose="version-sticker-verbose.txt"

cleanup_scrap_files() {
    rm -f "${_build_context}/${_scrap_prefix}"*
}

dump_environment() {
    ### List the selected environment variables.
    ### Just debugging support.

    echo "Environment dump:"
    echo "_build_context=${_build_context}"
    echo "_branch=${_branch}"
    echo "_blend=${_blend}"

    echo "_owner=${_owner}"
    echo "DOCKER_REPO=${DOCKER_REPO}"
    echo "DOCKER_TAG=${DOCKER_TAG}"
    echo "_deploy_repo=${_deploy_repo}"
    echo "_deploy_tags=${_deploy_tags[@]}"

    echo "FEATURES_BUILD_SLIM=${FEATURES_BUILD_SLIM}"
    echo "FEATURES_JQ=${FEATURES_JQ}"
    echo "FEATURES_NOVNC=${FEATURES_NOVNC}"
    echo "FEATURES_SCREENSHOOTING=${FEATURES_SCREENSHOOTING}"
    echo "FEATURES_THUMBNAILING=${FEATURES_THUMBNAILING}"

    echo "DOCKERFILE_PATH=${DOCKERFILE_PATH}"
    echo "BASEIMAGE=${BASEIMAGE}"
    echo "BASETAG=${BASETAG}"
    echo "VERSION_STICKER_PREFIX=${VERSION_STICKER_PREFIX}"
    echo "VERSION_STICKER_SUFFIX=${VERSION_STICKER_SUFFIX}"
}

encode_json_quotes() {
    ### Encode double-quotes for use in JSON
    echo "${1//\"/\\\"}"
}

encode_json_newlines() {
    ### Encodes new-lines for use in JSON
    echo $( echo -e "${1}" | sed -z 's/\n/\\n/g' )
}

get_label() {
    ### Returning the given label value via the predefined global variable.

    local repotag="$1"
    local label="$2"

    echo $( docker inspect "${repotag}" --format='{{ index .Config.Labels "'${label}'" }}' )
}

make_gist_filename() {
    ### Returns correctly formatted gist member file name

    local repo="${1?Need repo}"
    local tag="${2?Need repo tag}"
    local filename="${3?Need file name}"

    echo "$(basename ${repo})"@"${tag}"@"${filename}"
}

get_gist_file() {
    ### Gets the specified file from the secret gist.

    local gist=${1?Need gist ID}
    local repo="${2?Need repo}"
    local tag="${3?Need repo tag}"
    local filename="${4?Need file name}"
    local output_file="${5?Need output file}"

    local gist_filename
    local result

    gist_filename=$( make_gist_filename "${repo}" "${tag}" "${filename}" )

    ### assumption: 'output_file' is the full file name correctly composed by the caller
    ### note that the dummy parameter '?$(date +%s)' is added to the URL to avoid caching
    # set -x
    result=$(curl -s \
        -X GET \
        --write-out "%{http_code}" \
        -o "${output_file}" \
        -H "Accept: application/vnd.github.v3+json" \
        "https://gist.githubusercontent.com/${_owner}/${gist}/raw/${gist_filename}/?$(date +%s)")
    # set +x

    if [[ "${result}" == "200" ]] ; then
        echo "Gist file '${gist_filename}' saved as '${output_file}'."
        return 0
    elif [[ "${result}" == "404" ]] ; then
        echo ; echo "Gist file '${gist_filename}' not found."
        return 0
    else
        echo "Getting gist file '${gist_filename}' failed: ${result}"
        return 2
    fi
}

list_labels() {
    ### Listing all image labels.
    ### Just debugging support.

    local repotag="$1"

    # docker inspect "${repotag}" --format='{{println}} {{ range $k, $v := .Config.Labels -}} {{ $k }}={{ $v }} {{println}} {{end -}}'

    docker inspect "${repotag}" --format='
    {{ range $k, $v := .Config.Labels -}}
    {{ $k }}={{ $v }}
    {{end -}}'
}

update_gist() {
    ### Updating the secret GitHub gist containing datat (e.g. badge endpoints).
    ### 'GIST_TOKEN' secret (PAT) with the 'gist' scope is required

    local gist=${1?Need gist ID}
    local gist_key="${2?Need gist key}"
    local repo="${3?Need repo}"
    local tag="${4?Need repo tag}"
    local content="${5?Need content}"

    local data
    local envelope
    local gist_filename
    local result

    if [[ -z "${GIST_TOKEN}" ]] ; then

        echo "Skipping gist update. Required variables not set."
        return 0
    fi

    case "${gist_key}" in
        "${_gist_key_created}" )

            envelope='{"subject":"created","status":"'${content}'","color":"blue"}'
            ;;

        "${_gist_key_version_sticker}" )

            envelope='{"subject":"version sticker","status":"'${content}'","color":"blue"}'
            ;;

        "${_gist_key_version_sticker_verbose}" )

            envelope="${content}"
            ;;
        * )
            echo "Skipping gist update. Unsupported gist key '${gist_key}'."
            return 0
            ;;
    esac

    gist_filename=$( make_gist_filename "${repo}" "${tag}" "${gist_key}" )

    ### encode double-quotes
    # envelope="${envelope//\"/\\\"}"
    envelope=$( encode_json_quotes "${envelope}" )

    ### encode new-lines
    # envelope=$( echo "${envelope}" | sed -z 's/\n/\\n/g' )
    ### be careful with quotes!
    envelope=$( encode_json_newlines "${envelope}" )
    
    data='{ "files": { "'${gist_filename}'": { "filename": "'${gist_filename}'", "content": "'${envelope}'" } } }'

    echo "Updating gist '${gist_filename}'"

    ### required 'GIST_TOKEN' (PAT) scope is 'gist'
    result=$(curl -s \
        -X PATCH \
        -o /dev/null \
        --write-out "%{http_code}" \
        -H "Authorization: token ${GIST_TOKEN}" \
        -H "Accept: application/vnd.github.v3+json" \
        https://api.github.com/gists/${gist} \
        -d "${data}")

    if [[ "${result}" == "200" ]] ; then
    
        echo "Gist '${gist_filename}' updated successfully"
        echo
        return 0
    else
        echo "Gist '${gist_filename}' update failed: ${result}"
        echo 
        return 1
    fi
}